Rolling mill



K. HUBER I June 19, 1934.

ROLLING MILL Filed D60. 19, 1931 Patented June 19, 1934 UNITED STATES PATENT OFFICE Application December 19, 1931, Serial No. 582,149 In Germany December 19, 1930 2 Claims.

My invention relates to rolling mills especially adapted for hot and cold rolling of metal bands and sheets.

In hot and cold rolling strips of small thickness '3 and thin metal sheets it is endeavored to give as small a diameter as possible to the working rolls of the multi-roller appliance (rolling mills with four and six rolls) which are supported by supporting rollers.

Rolling with such rolls of small diameter affords inter alia the following advantages.

In consequence of the smaller deflection of the supported working rolls a bigger reduction in thickness can be effected at a single operation than in the case of rolls of greater diameter, so that fewer operations are required for rolling to a definite final thickness and consequently the total power consumption also is reduced.

In consequence of reduced spreading, the elongation of the rolled material increases and in spite of larger decrease in thickness in consequence of this greater extension the edges of the rolled material do not crack.

In cold rolling the compacting of the material (increase in tensile strength, cold hardening) is much less than when rolling is effected with rolls of greater diameter so that on one hand the material can be more readily drawn and on the other hand intermediate annealing operations for enabling the further treatment of the rolled material are reduced.

In addition apart from the advantage of smaller weight and more facile manufacture of the smaller rolls, there is the advantage that the entire rolling mill can be of a lighter con- 0 the smaller diameter of the rolls, there is the disadvantage that the bite is reduced as with the same initial thickness of the material and with the same reduction in thickness under otherwise equal conditions (composition of the material being rolled, temperature at which rolling is effected, roughness of the outer surface of the rollers, etc.,) rolls with a larger diameter grip the material better (smaller angle of bite) than rolls of smaller diameter (larger angle of bite). This disadvantage, however is all the more of small practical importance for the application of rolls of small diameter for rolling strips and metal sheets which initially are already of small thickness, because there are means available for increasing the friction between rolled material and rolls and thus for increasing the bite.

If it were possible still further to reduce the diameter of the working rolls then the abovementioned advantages which are afforded in roll- 66 ing, would be increased appreciably. The utilization of this advantage is, however, limited by the rolls in their present form and by the mode in which they are driven in which the drive is applied from one side only. The reasons are as follows: 7

Of the three characteristic cross sections through the roll of the construction hitherto'employed (body, neck and Wobbler) that of the wobbler is the smallest. Its magnitude is determined by the maximum torque which it has to transmit at the maximum rolling pressure. The crosssection of the body, of the roll which is supported over the entire length of the body and is thus mounted in a manner preventing bending, an arrangement for which various forms have already been proposed, has also to withstand the pressures and tensions which occur due to the rolling pressure in addition to this torque. In order to take up this composite maximum strain it is necessary to employ a minimum cross-section of the body which cross-section however is greater than that of the Wobbler. This cross-section which is adequate mathematically, must be increased further by the amount by which the ball is to be turned or ground down in consequence of surface wear. In practice however the rollers could not be used. even with this somewhat increased cross-section because the diameter of the Wobbler together with the coupling sleeve which 9&

embraces the Wobbler is greater than that of the body. Thus in the usual drive of the rollers from one side only the coupling sleeves would come into contact before the bodies of the rolls and it was therefore not possible to adjust these to contact with one another i. e., it was only possible to roll sections the thickness of which was greater than the difference between the diameter of the coupling sleeve and the body of the roll.

Now a rolling mill has already been proposed in which for obviating the difficulties above set forth the drive of the two rolls is effected from different sides of the housings and in which the rolls are constructed non-symmetrically. This proposal could not however have any practical significance because the new difficulties involved in such a construction of the rollers and particularly those concerned with the mounting of the rollers and securing them against axial displacement were insufficiently considered.

The present invention now shows the method in which the known advantage of minimum diameter of the body of the roll can be utilized in a manner which is correct from the constructional and mechanical aspect. For this purpose nonsymmetrical rollers known per se are used and are supported wholly or in part over the entire length of the body of the roll, but according to the invention the body has the smallest diameter, the collar serving for securing the roller against axial displacement has the largest diameter and the Wobbler has an intermediate diameter lying between these two magnitudes.

The essential difference between the novel roll and the rolls of the construction which hitherto the roll, particularly those of the Wobbler and the collar.

The body serves both as working and bearing surface, the collar prevents axial displacement of the roll in one direction and the Wobbler serves the same function as the'wobbler of rolls of usual construction. V 7

Various constructions of rolling mills embodying this novel roll are illustrated by Way of example in the accompanying drawing in which:

-Fig.'1 shows a front elevation and Fig. 2 an end elevation of the novel roll,

Fig. 3 shows a side View of a six roll mill equipped with such rolls and I 'Fig. 4 a front view partly in section of Fig. 3.

The rolls consist of the body'w, the collar 1) and the Wobbler k.

There are different ways possible'in which the novel roll can be mounted; one of the same is shown.

The roll is mounted between two supporting rollers in such manner that the body w is sup- (a) Greatest possible reduction in thickness at one operation.

(b) Smallest broadening and thus avoidance of marginal fissures.

(c) Avoidance of marginal cutting of the strip iron.

(d) Reduction in the total power consumption in consequence of reductionin the number of stages. 1

(2) Reduced cold-hardening during cold rolling, and, thus increase in the capacity to be drawn and consequently (j) Economy in intermediate annealing operations (g) Reduction in the weight of the rolls (h) Dispensing with the interior cooling of the roll' (2') Reduction in the cost of production of the rolled articles in consequence of the advantages enumerated under (a)(h) What I claim is:

l; A rolling mill especially adapted for hot and cold rolling of metal bands and sheets comprising a frame, rolls extending into the frame from opposite directions, a collar on each roll, a wobbler on each roll, supporting rolls in the frame for supporting one end portion of the working part of the rolls directly and exclusive- 1y, said frame having side bearings against which the collars work, theworking parts of the rolls having the smallest and the collars the greatest diameter, the diameter of the collars being sufiiciently large to bear against their respective bearings in the frame.

. 2. A rolling mill especially adapted for hot and cold rolling of metal bands and sheets comprising a frame, rolls projecting into the frame in opposite directions, a collar on each roll integral therewith and a Wobbler on each roll, supporting rolls in the frame for supporting one end portion of the working part of the said oppositely extending rolls directly and exclusively, said frame having side bearings against which the respective collars work, the working part of each roll having the smallest and the collars the greatest diameter, the diameter of the collars being sufficiently large to cause, thecollars to bear against the respective bearings in the frame to take up axial thrust.

' KARL HUBER. 

